Displays and DPI
Computer screens and images are measured in pixels and Snagit on Mac captures the screen at actual pixel size. When an image is printed, those pixels are divided up across the print area which is measured in inches. The resulting calculation is known as "dpi" which stands for dots (pixels) per inch.
Most displays have a much lower dpi than a printed page. Older computer screens might be 72 or 96 dpi, while modern LCD screens are often in the 120-140 dpi range. Standard print resolution for a letter-sized page is 300 dpi.
As an example, a 13" MacBook Pro has a screen size of 1280 x 800 pixels. A fullscreen capture, printed at 300 dpi, would be about 4 1/4" x 2 2/3", much smaller than the physical dimensions of the screen. An US Letter sized sheet of paper at 300 dpi (8 1/2" x 11") would require an image of 2550 x 3300 pixels, much larger than most computer displays.
Resizing and Converting
If you are preparing images for printing, you may need to set a specific resolution such as 300 dpi. Snagit for Mac can resize images but cannot directly set the image dpi. Other image editors like Apple Preview or Adobe Photoshop can set dpi.
To enlarge a screen capture in Snagit for Mac, use the Edit->Resize Image command. You can resize to specific dimensions or by a percentage. Resizing a screen capture can result in a blurry or pixelated image so we recommend testing your output for quality. If you need to set dpi, use File->Save As and create a new file (often TIFF or JPEG will be used for printing) then open that new image in Preview or Photoshop. In Preview, use the Tools->Adjust Size command; in Photoshop use Image->Image Size.
Images intended for offset press printing may also need to use the CMYK (Cyan, Magenta, Yellow, Black) color model rather than RGB (Red, Green, Blue) which is used for computer displays. Snagit for Mac and Preview cannot convert images from RGB to CMYK; this would require a professional image editor such as Photoshop.
Printing with Snagit
Snagit can print captures directly as well. Since Snagit on Mac is not a page-based program, it does not have page layout or sizing controls. Some printers will have sizing options such as Scale or Fit to Page in the Page Setup or Print dialog; this depends on what the printer manufacturer included in their driver. For better control over print layout, you may want to print your capture from a page-based program such as Word, Pages, or InDesign.